POSTER: A Comprehensive Study of Forged Certificates in the Wild

With the widespread use of SSL, many issues have been exposed as well. Forged certificates used for MITM attacks or proxies can make SSL encryption useless easily, leading to privacy disclosure and property loss of careless victims. In this paper, we implement a large scale of passive measurement of SSL/TLS and analyze the forged certificates in the wild comprehensively. We measured SSL/TLS connection for 16 months on two large research networks, which provided a total of 100 Gbps bandwidth. We gathered nearly 135 million leaf certificates and studied the forged ones. Our findings reveal main reasons of signing forged certificates, and show the preference of them. Finally, we find out several suspicious servers that might be used for MITM.